Torque converters used with conventional automatic transmissions typically transmit torque in a single direction. Planetary gears in the transmission are easily configured to operate the vehicle in reverse. Unfortunately, CVT transmissions must incorporate an additional planetary gear to achieve reverse when used with a conventional torque converter, increasing the cost and complexity of the transmission.
Commonly owned U.S. Pat. No. 6,050,375 (granted Apr. 18, 2000 to Gradu et al. for “HYDROKINETIC TORQUE CONVERTER”), herein incorporated by reference, discloses a torque converter which achieves a reverse mode in a CVT transmission without the need for an additional planetary set. Gradu et al. disclose additional synchronizing mechanisms or units which are designed to conform the RPM of a driving part to the RPM of a driven part before such parts are positively (such a form-lockingly) connected to each other. Gradu et al. also disclose a thrust bearing between and rotatably coupling coaxial hubs to each other for joint movement in the axial direction of the torque converter. It would be desirable to eliminate the need for the additional synchronizing mechanisms and thrust bearings.
Thus there is a long-felt need for a torque converter design whereby additional synchronizing mechanisms and thrust bearings are not needed for operation in reverse.